Heterogeneous Non-noble Catalyst for Highly Selective Production of Linear α-Olefins from Fatty Acids: A Discovery of NiFe/C

Article abstract of DOI:10.1002/cssc.202001356

Catalytic deoxygenation of even-numbered fatty acids into odd-chain linear α-olefins (LAOs) has emerged as a complementary strategy to oligomerization of ethylene, which only affords even-chain LAOs. Although enzymes and homogeneous catalysts have shown promising potential for this application, industrial production of LAOs through these catalytic systems is still very difficult to accomplish to date. A recent breakthrough involves the use of an expensive noble-metal catalyst, Pd/C, through a phosphine ligands-assisted method for LAOs production from fatty acid conversion. This study presents a unique, cost-friendly, non-noble bimetallic NiFe/C catalyst for highly selective LAOs production from fatty acids through decarbonylative dehydration. In the presence of acetic anhydride and phosphine ligand, a remarkable improvement in the yield of 1-heptadecene from the conversion of stearic acid was found over the supported bimetallic catalyst (NiFe/C) as compared to corresponding monometallic counterparts (Ni/C and Fe/C). Through optimization of the reaction conditions, a 70.1 % heptadecene yield with selectivity to 1-heptadecene as high as 92.8 % could be achieved over the bimetallic catalyst at just 190 °C. This unique bimetallic NiFe/C catalyst is composed of NiFe alloy in the material bulk phase and a surface mixture of NiFe alloy and oxidized NiFe^δ+ species, which offer a synergized contribution towards decarbonylative dehydration of stearic acid for 1-heptadecene production.

Full text of DOI:10.1002/cssc.202001356

Chemistry–Sustainability–Energy–Materials
Accepted Article
Title: Heterogeneous Non-noble Catalyst for Highly Selective
Production of Linear α-Olefins from Fatty Acids: A Discovery of
NiFe/C
Authors: Zihao Zhang, Wenwen Lin, Yafei Li, Francis Okejiri, Yubing
Lu, Jixing Liu, Hao Chen, Xiuyang Lu, and Jie Fu
This manuscript has been accepted after peer review and appears as an
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To be cited as: ChemSusChem 10.1002/cssc.202001356
Link to VoR: https://doi.org/10.1002/cssc.202001356
0
1/2020

ChemSusChem
10.1002/cssc.202001356
DOI: 10.1002/anie.201((will be filled in by the editorial staff))
Biomass Conversion
Heterogeneous Non-noble Catalyst for Highly Selective Production of Linear α-
Olefins from Fatty Acids: A Discovery of NiFe/C
Zihao Zhang, Wenwen Lin, Yafei Li, Francis Okejiri, Yubing Lu, Jixing Liu, Hao Chen, Xiuyang Lu, Jie Fu*
Abstract: Catalytic deoxygenation of even-numbered fatty acids into
odd-chain linear α-olefins (LAOs) has emerged as a complementary
strategy to oligomerization of ethylene, which only affords even-
chain LAOs. Although enzymes and homogeneous catalysts have
shown promising potential for this application, industrial
production of LAOs through these catalytic systems is still very
difficult to accomplish up to present. A recent breakthrough involves
the use of expensive noble-metal catalyst - Pd/C through a
phosphine ligands-assisted method for LAOs production from fatty
acid conversion. This study, therefore, presents a unique, cost-
friendly, non-noble bimetallic NiFe/C catalyst for highly selective
LAOs production from fatty acid through decarbonylative
dehydration. In the presence of acetic anhydride and phosphine
ligand, we found a remarkable improvement in the yield of 1-
heptadecene from the conversion of stearic acid over the supported
bimetallic catalyst (NiFe/C) as compared to corresponding
monometallic counterparts (Ni/C and Fe/C). Through optimization
of the reaction conditions, a 70.1% heptadecene yield with
selectivity to 1-heptadecene as high as 92.8% can be achieved over
the bimetallic catalyst at just 190 °C. This unique bimetallic NiFe/C
catalyst is composed of NiFe alloy in the material bulk phase and a
surface mixture of NiFe alloy and oxidized NiFeδ+ species, that offer
a synergized contribution towards decarbonylative dehydration of
stearic acid for 1-heptadecene production.
derived even-numbered fatty acids has emerged as a complementary
[
4]
strategy.
Various forms of catalytic systems including
homogeneous and heterogeneous forms have all been investigated in
[
4e]
this application.
However, the exploration of heterogeneous
catalytic systems as the most realistic approach for industrial
production of LAOs from the fatty acid conversion is still very
[
3a,5]
understudied.
The relatively low popularity of heterogeneous catalytic
systems towards the conversion of fatty acids is probably ascribed to
their relatively low selectivity to LAOs production due to the
occurrence of side reactions such as isomerization and/or
decarboxylation to saturated alkanes. Lopez-Ruiz and co-workers
reported the use of Pt- and Pd-supported catalysts for
decarbonylative dehydration of heptanoic acid to produce LAO with
[
6]
relatively high selectivity (57%) over gas-phase operations. The
selectivity to LAO production was only 15% over the liquid-phase
[
6a]
operations (Scheme 1). Maetani et al. reported a very promising
non-noble Fe complex catalyst with high selectivity to LAOs from
decarbonylation of fatty acid, but its reuse performance was not
[
4d]
mentioned. Also, a selectivity to LAO production as high as 90%
has been reported over a Lewis-acid gamma-Al or WO –Al
catalyst through a transformation of biomass-derived lactones, but
2
O
3
x
2 3
O
[
7]
the choice of reactants is only limited to unsaturated acids. To
circumvent these challenges, a recent study from Jensen and co-
workers (Scheme 1) utilized expensive commercial Pd/C catalyst in
the presence of optimized phosphine ligands (DPEphos, the
molecular structure shown in Figure S1) to achieve high selectivity
L
inear α-olefins (LAOs) with terminal carbon-carbon double bond
are important building blocks for the fabrication of a wide range of
value-added chemicals including polyolefins, detergents, lubricants,
[8]
of LAOs production from fatty acid conversion. Despite this
breakthrough, the development of an inexpensive, non-noble metal-
based heterogeneous catalyst for high selectivity of LAOs
production from the fatty acid conversion is highly desirable from
an economic standpoint.
[
1-5]
plasticizers, synthetic oils, etc.
A dominant preparation method,
at present, involves the oligomerization of ethylene derived from
[
6-8]
fossil resources.
This preparation strategy, however, has three
main drawbacks: 1) raw materials are mainly derived from
petroleum resources; 2) precise control of the growth of carbon
chain to target a single product is a difficult task to accomplish, and
3
) the as-obtained LAOs are always certainly even-numbered.[3]
Consequently, catalytic decarbonylative dehydration of biomass-
[]
Dr. Z. Zhang, W. Lin, Y. Li, Dr. H. Chen, Dr. X. Lu, Dr. J. Fu. Key
Laboratory of Biomass Chemical Engineering of Ministry of
Education, College of Chemical and Biological Engineering,
Zhejiang University, Hangzhou 310027, China. E-mail:
jiefu@zju.edu.cn Z. Zhang and W. Lin contributed equally
Dr. Z. Zhang, W. Lin, Dr. J. Fu. Institute of Zhejiang University -
Quzhou, 78 Jiuhua Boulevard North, Quzhou 324000, China
Scheme 1. Schematic representation of already reported and our proposed
NiFe catalytic scheme
F. Okejiri, Dr. J. Liu, Department of Chemistry, The University of
Tennessee, Knoxville, TN 37916, USA
Herein, we report, for the first time, a supported bimetallic -
NiFe/C catalyst for the efficient and highly selective production of
Dr. Y. Lu, Institute for Integrated Catalysis, Pacific Northwest
National Laboratory, 902 Battelle Blvd., Richland, WA 99352, USA
1
-heptadecene from decarbonylation dehydration of stearic acid in
[]
Supporting information for this article is available
the presence of Ac
2
O and phosphine ligands. The bimetallic NiFe/C
1
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ChemSusChem
10.1002/cssc.202001356
catalyst with Ni/Fe ratio of 1 showed significant improvement in
yield of 1-heptadecene from the conversion of stearic acid as
compared to the monometallic counterparts (Ni/C and Fe/C) as well
as other NiFe/C catalysts with different Ni/Fe ratios. A series of
characterizations techniques including powder X-ray diffraction
respectively confirm the presence of larger crystallite of Fe in Fe/C
catalyst.
The reduction behavior of the calcined catalysts was
investigated via the temperature-programmed reduction experiment
of H
2
(H
2
-TPR). The results are shown in Figure 2. The Ni/C
/C) has the H -consumption peak at
(
(
PXRD), inductively coupled plasma-optical emission spectroscopy
ICP-OES), N adsorption-desorption isotherms and temperature-
catalyst precursor (NiO
x
2
2
~183 °C and another reduction peak above 500 °C attributed to the
reduction of activated carbon (AC) carrier as equally observed in
programmed desorption measurements were used to investigate the
chemical structure, composition, physical and chemical properties of
catalysts. Also, transmission electron microscopy (TEM), energy-
dispersive X-ray spectroscopy (EDS) mapping, and temperature-
programmed reduction measurements were used to provide direct
evidence of the existence of NiFe alloy in the bimetallic catalyst.
The valence states of Ni and Fe surfaces were investigated using X-
ray photoelectron spectroscopy (XPS). The catalytic activity of the
bimetallic NiFe/C catalyst was optimized by varying different
reaction conditions, and the plausible reaction pathway for the
conversion process was provided.
[
13]
our previous study.
(NiFeO /C), the reduction temperature increases to 290 °C, which
implies that the NiFeO solid solution is much more difficult to
reduce. The reduction of Fe
Fe in dry H /Ar atmosphere.
For the NiFe/C bimetallic precursor
x
x
2
O
3
involves two steps: Fe
2
O
3
→ Fe
3
O
4
[
14]
→
2
Therefore, the small H
2
-
consumption peak located at 336 °C is ascribed to the reduction of
8
Fe
reductions overlaps with that of AC carrier. The absence of peak
attributed to Fe → Fe in NiFe/C catalyst also collaborates the
formation of NiFe alloy, in agreement with the XRD result. It should
be noted that the consumption of H by Fe/C precursor is almost 1.5-
2 3 3 4 3 3 4
O (+3) to Fe O (+ / ), as the peaks attributed to Fe O → Fe
3
O
4
2
fold greater than that of Ni due to the higher valence state of Fe in
the oxide form.
Figure 1. XRD patterns of reduced Ni/C, Fe/C, and representative NiFe/C
catalysts.
2
Figure 2. H -TPR profiles of Ni/C, Fe/C, and representative NiFe/C before
reduction
The PXRD patterns of Ni/C, Fe/C, and a representative
NiFe/C catalysts were recorded and presented in Figure 1. All three
catalysts display broad diffraction peak at 2θ approximately 24°,
which is ascribed to the reflection of the amorphous carbon
Based on the N
S2a, the AC support alongside all three catalysts (Ni/C, NiFe/C, and
Fe/C) showed high adsorption amount of N at low relative pressure.
All four samples exhibit the type-IV adsorption isotherm with H3-
type hysteresis loop, suggesting the existence of rich micropores and
2
adsorption-desorption isotherms in Figure
[
9]
support. The diffraction pattern of Ni/C catalyst has three main
peaks at 2θ value of 44.5, 51.8, and 76.4° attributed to (110), (200)
and (202) reflections of metallic Ni with face-centered cubic (fcc)
2
[
10]
lattice (JCPDF #04-0850). Similarly, the three main peaks at 2θ
of 44.7, 65.0 and 82.3° corresponding to (110), (200) and (211)
reflections respectively were observed for the Fe/C catalyst,
indicating the presence of metallic Fe with body-centered cubic (bcc)
lattice (JCPDF #06-0696). For the bimetallic NiFe/C catalyst, the
diffraction pattern very closely adopts the fcc crystal structure Ni
with the three main diffraction peaks (43.8, 50.8, and 74.9°) slightly
shifted towards lower 2θ. This suggests that the bulk of Fe
successfully migrated into the fcc Ni matrix to form the fcc NiFe
alloy structure in the bimetallic NiFe/C catalyst.[ Notably, the
NiFe/C catalyst also exhibits some characteristic bcc-lattice-related
diffraction peaks located between bcc Fe and fcc Ni, which are
possibly due to the formation of small amounts of bcc NiFe alloy
structure. We can speculate from these observations that our
bimetallic NiFe/C catalyst is composed of both fcc and bcc NiFe
alloy structure, but predominantly fcc NiFe alloy. It should be noted
that the diffraction peaks of Fe/C catalyst are much sharper than
those of Ni/C and NiFe/C catalysts, indicating its large crystallite
size. The average crystallite size of Fe, NiFe, and Ni for the Fe/C,
NiFe/C, and Ni/C catalysts was estimated using Scherrer equation,[12]
and the obtained values of 38.7 nm, 13.2 nm, and 10.4 nm
[
15]
mesopores.
All three catalysts exhibit similar surface area, total
pore volume, and pores size distribution (Table S1, Figure S2b).
These values are slightly lower those of the AC support. For
example, the surface area of the AC support, Fe/C, FeNi/C, and
2
Ni/C catalysts are 776.9, 759.3, 745.5, and 762.0 m /g respectively.
Therefore, the presence of active site (Ni and Fe) on the AC support
has no significant change in the pore structure but does reduce
porosity. The temperature-programmed desorption of CO (CO-TPD)
results for all three catalysts are shown in Figure S3. Based on the
CO-TPD profiles, the chemisorbed CO on the Ni/C catalyst has
conspicuously lower desorption temperature as compared to that of
Fe/C and NiFe/C. The relatively stronger adsorption ability of
NiFe/C compare to Ni/C towards CO is perhaps beneficial to the
decarbonylation reaction presented in this work.
The transmission electron microscopy (TEM) images of Ni/C,
NiFe/C, and Fe/C catalysts are shown in Figure 3(a,c,e). The
relatively darker sphere-like regions have been identified as the
metal particles. The particle size of Ni in the Ni/C catalyst is smaller
than that of Fe in Fe/C catalyst. The average particle size
distributions of Ni/C, NiFe/C, and Fe/C catalysts are shown in
11]
2
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ChemSusChem
10.1002/cssc.202001356
Figure 3(b,d,f). The particle size of Ni/C, NiFe/C, and Fe/C
catalysts showed a similar trend with the crystallite size value (XRD
result) and have been calculated to be 7.0, 19.8, and 32.1 nm
respectively (the statistical regions are shown in Figure 3c and
Figure S4). Furthermore, the EDS elemental map of the bimetallic
NiFe/C catalyst was acquired to demonstrate the existence of NiFe
alloy in the representative NiFe/C catalyst. Based on the results
shown in Figure 4, both Ni and Fe X-ray signals are evenly
distributed in the sample regions, which is strong evidence of the
formation of metal alloy. Additionally, the line-scanning result of a
single particle of NiFe/C (Figure 4e) equally shows the existence of
NiFe alloy with molar ratios close to 1. A representative image of a
single NiFe alloy can be seen in Figure 4d, showing encapsulation
of NiFe alloy by the amorphous carbon support.
X-ray photoelectron spectroscopy (XPS) was used to
investigate the chemical states of the catalyst surface. Figure 5a
displays the XPS profiles of NiFe/C and Fe/C catalysts in the Fe 2p
2
+
3+
region, showing the overlap of oxidated Fe (Fe and Fe ) with the
2
+
satellite peak of Fe between 709 eV to 716 eV. The NiFe/C catalyst
0
in particular has a small iron peak in Fe state which is visibly
[
16]
absent in Fe/C catalyst.
Also, the XPS spectra of Ni/C and
NiFe/C in the Ni 2p region shown in Figure 5b both have the
0
characteristic peak at 853.2 eV ascribed to metallic nickel (Ni ).
Additionally, the main peak at 856.2 eV together with the satellite
2
+ [17]
peak at 861.7 eV confirms the existence of oxidized nickel (Ni ).
The above results suggest that both Ni and Fe surfaces are well
oxidized upon exposure to air. Therefore, we acknowledge the
existence of oxidized states of the catalyst on the surface alongside
zero oxidation state (metallic species) of the material bulk in the
NiFe/C catalyst as the main active sites of the catalyst.
Figure 3. TEM images of (a) Fe/C, (c) NiFe/C and (e) Ni/C catalysts and their
Figure 5. (a) Fe 2p XPS spectra of Fe/C and NiFe/C catalysts; (b) Ni 2p XPS
corresponding (b,d,f) average particle size distributions.
spectra of Ni/C and NiFe/C catalysts.
The catalytic activity of the bimetallic NiFe/C catalysts and
the monometallic counterparts - Fe/C and Ni/C was investigated
towards stearic acid conversion at 190 °C for 16 h in the presence of
DPEphos and Ac
summarized in the caption of Figure 6. The choice of Ac
ascribed to its excellent promoting effect on decarbonylative
2
O. The detailed reaction conditions are
2
O is
[
18]
reactions, based on the work from Michal et al.
Prior to the
determination of the efficiency of our representative bimetallic
catalyst, a preliminary experiment was first conducted to determine
the optimized ratio of Ni and Fe in the bimetallic catalyst. The result
is presented in Figure S5. Among different Ni/Fe ratios under
review (1:3, 1:2, 1:1, 2:1, and 3:1), the bimetallic NiFe catalyst with
a Ni/Fe ratio of 1 showed the highest yield of heptadecene and 1-
heptadecene under similar reaction conditions, and hence adopted as
our represented catalyst. As seen in Figure 6, the respective yields
of heptacene in Ni/C and Fe/C (both 10 wt% metal loading)
catalysts are 29.4% and 12.6% with an α-heptadecene yield of
Figure 4. (a) TEM and (d) HRTEM images of NiFe/C catalyst, and the
corresponding (e) line-scanning of single particle and (b,c,f) EDS-mapping of
selected region results.
2
23.8% and 11.6% respectively. In all DPEphos-Ac O reaction
systems, the selectivity to α-olefin production in both Ni/C and Fe/C
3
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ChemSusChem
10.1002/cssc.202001356
catalytic systems is very high, however, their catalytic activity
towards the yield of heptadecene is quite low. Conversely, the
bimetallic NiFe/C catalyst with similar total metal loading (5 wt%
Ni and 5 wt% Fe) displayed remarkably improvement in the yields
of both heptadecene (66.3%) and 1-heptadecene (60.1%). To
underscore the advantage of our unique bimetallic NiFe/C catalyst,
the catalytic activity of a physically mixed Ni/C and Fe/C catalyst
performance for the catalytic deoxygenation of other fatty acids with
different carbon chain numbers (Figure S8).
Considering many similarities between our NiFe/C
heterogeneous catalyst and already reported Pd/C-based
2
heterogeneous catalytic system in the presence of Ac O and
bis(phosphine) for the conversion of fatty acid, we proposed
reaction mechanism for our NiFe/C catalytic system, similar to that
[
8]
(Ni/C + Fe/C) with mole ratio (determined via ICP-OES, Table S2)
already reported for Pd/C catalytic system.
The plausible
similar to our optimized bimetallic NiFe/C catalyst, was investigated. conversion pathway is summarized in Figure 7. Firstly, the metallic
0
The results revealed that a simple mixture of Ni/C and Fe/C
catalysts can only afford a 24.4 % heptadecene yield which is
significantly lower 66.3% heptadecene yield observed over our
bimetallic NiFe/C catalyst. Through optimization of the reaction
time (8 h, 16 h, and 24 h), the bimetallic NiFe/C catalyst can afford
a heptadecene yield as high as 70.1% with a selectivity to 1-
heptadecene close to 95% (Table S3, entries 1-3). Chatterjee and co-
workers opined that the inability of olefins yields to proceed beyond
NiFe catalyst with the attached DPEphos ligand can react with
mixed anhydride obtained from the transformation of stearic acid
and Ac
carboxylate;
carboxylate proceeds through CO loss to produce an unstable
intermediate. The third step proceeds through classical β-hydride
elimination of this unstable intermediate to eliminate the alkene with
the formation of the metal-bonded hydride. Lastly, the catalytic
cycle is complete via the dissociation and elimination of 1-
heptadecene and catalyst regeneration.
δ+
2
O via oxidative addition reaction to give a NiFe acyl
[
8,19]
Secondly, decarbonylation of the acyl ligand
[
8]
7
0% over Pd/C catalyst in DPEphos-Ac
due to the formation of highly concentrated unsaturated olefins (near
0% yield) and decarbonated product CO, which occludes the
2
O reaction system is mainly
7
[
8]
catalyst pores and poisons the active sites. In this work, our
NiFe/C catalytic system appears to have had similar limitations.
Figure 6. The yield of heptadecene and 1-heptadecene from conversion of
stearic acid over NiFe/C, Ni/C, Fe/C and physical mixture of Fe/C and Ni/C
catalysts. Reaction conditions: T = 190 °C, t = 16 h, Ac
0 mg, stearic acid = 50 mg, catalyst = 30 mg.
2
O = 30 μL, DPEphos =
3
Figure 7. Plausible reaction pathway of NiFe/C-catalyzed decarbonylation
dehydration of stearic acid.
As previously established, our NiFe/C catalyst is composed of
bulk NiFe alloy and surface-oxidized NiFeO and NiFe alloy
components. To underscore the importance of NiFe alloy on the
yield of heptadecene and 1-heptadecene selectivity, we investigated
x
Here, we provide one possible explanation for the enhanced
catalytic performance of bimetallic NiFe/C catalysts. As seen in
Figure 7, the decarbonylation and β-hydride elimination are the two
key steps for producing linear α-olefins (LAOs) with high selectivity.
also the catalytic performance of NiFeO
x
/C sample; where
2
reduction step. The
NiFeO /C is the NiFe/C precursor before the H
x
2
In the presence of Ac O and phosphine ligand, decarboxylation
obtained yield of heptadecane and 1-heptadecene selectivity was
limited to 5.9 and 23.7 % alone respectively (entries 4 of Table S3).
reaction for the production of saturated alkanes will be inhibited
with decarbonylation as a preferred route. The good catalytic
performance over Pd/C could be ascribed to its outstanding
Conversely, NiFe/C-O
of the reduced NiFe/C catalyst surface in 10% O
h at room temperature showed catalytic activity that is comparable
to our optimized NiFe/C catalytic system. It is important to state that
the as-obtained NiFe/C-O catalyst surface has similar Ni and Fe
2
catalyst obtained via immediate passivation
2
/Ar atmosphere for
decarboxylation/decarbonylation
and
β-hydride
elimination
its high
2
[
20]
activity.
Ni
was
recognized
for
decarbonylation/decarboxylation reactivity, and Fe was known for
2
its favorable β-hydride elimination property in the previous studies.
chemical structure as NiFe/C catalyst (Figure S6), and as a result,
gave a heptadecene yield of 60.3% and a selectivity to 1-
heptadecene of 92.3%. We believe that the NiFe alloy of the catalyst
[
9,21]
However, a simple mixture of Ni/C and Fe/C (Figure 6) didn’t
witness an activity improvement, which might be due to the
decarbonylation intermediate on Ni is difficult to move onto the Fe
for the subsequent β-hydride elimination reaction. In contrast, Ni-Fe
uniform alloy with Ni and Fe atoms closely linked together provides
a unique synergism with the Ni-dominant decarbonylation and the
subsequent Fe-dominant β-hydride elimination processes. Therefore,
our NiFe/C heterogeneous catalytic system provides a cost-effective,
x
bulk and surface oxidized NiFeO and NiFe alloy components are
responsible for high selectivity to 1-heptadecene production in this
present work. More importantly, the catalytic performance of our
novel NiFe/C catalyst is still very much pronounced even at a
catalyst loading as low as 1 mg (Figure S7). More importantly, the
bimetallic NiFe/C catalyst also exhibits outstanding catalytic
highly selective method of producing α-olefins through
a
4
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ChemSusChem
10.1002/cssc.202001356
transformation of biomass-derived fatty acid, since no expensive
noble metal such as Pd or Pt is utilized in the catalytic system.
In summary, monometallic (Ni/C and Fe/C) and bimetallic
NiFe/C catalysts were synthesized and evaluated for
decarbonylative dehydration of stearic acid in the presence of acetic
anhydride and phosphine ligand to produce α-olefins. Interestingly,
the bimetallic NiFe/C catalysts showed remarkable improvement in
yield of 1-heptadecene from the conversion of stearic acid in
comparison to monometallic counterparts - Ni/C and Fe/C. This
significant improvement in catalytic activity cannot be realized by a
mere mixture of Ni/C and Fe/C catalysts in a mole ratio similar to
our optimized bimetallic NiFe/C catalyst. Through optimization of
the reaction conditions, a heptadecene yield of 70.1% with
selectivity to 1-heptadecene as high as 92.8% can be achieved over
NiFe/C bimetallic catalyst at just 190 °C. Our NiFe/C bimetallic
catalyst is composed of NiFe alloy in the material bulk and a surface
Identification of the products was done by matching the retention
times of the unknown compounds to those of reference standards.
The quantitative analysis was performed using external calibration
curves for each compound. The conversion of stearic acid and yields
of products were calculated using the equations below. The reported
data are average values of three independent experiments. The
calculated conversion and yields of products were all based on the
equivalent amount of carbon. The selectivity to 1-heptadecene is
determined by dividing moles of achieved 1-heptadecene by moles
of generated heptadecene. The error bars represent the standard
deviation of three replicate experiments.
moles of remaining reactant
Conversion(%) =1-
100%
moles of reactant added
moles of product
moles of reactant added
Yield(%) =
100%
δ+
mixture of NiFe alloy and oxidized NiFe species.
Received: ((will be filled in by the editorial staff))
Published online on ((will be filled in by the editorial staff))
Experimental Section
Materials
Acknowledgements
Acetone (99.5%), Acetic anhydride (Ac
Ni(NO ·6H O (99%) were obtained from Sinopharm Chemical
Reagent Co., Ltd. Activated carbon and Bis(2-
diphenylphosphinophenyl)ether (DPEphos) were both purchased
from Sigma-Aldrich, USA. Fe(NO ·9H (99.99%) was
2
O, 98%), and
3
)
2
2
This work was supported by the National Natural Science Foundation of China
(
No. 21978259), the Zhejiang Provincial Natural Science Foundation of China
No. LR17B060002), and the Fundamental Research Funds for the Central
(
3
)
3
2
O
Universities.
purchased from Aladdin Industrial Corporation, China. Stearic acid
was bought from Mecklin Co., China. 1-heptadecene (99.5%) was
acquired from TCI (Shanghai) Development Co., Ltd. All chemicals
were directly used without purification.
Keywords: biomass conversion; linear α-olefins; bimetallic Ni-Fe;
fatty acids; decarbonylative dehydration
Catalyst synthesis
[
1] a) S. H. Hopen Eliasson, A. Chatterjee, G. Occhipinti, V. R. Jensen,
ACS Sustainable Chem. Eng. 2019, 7 (5), 4903-4911; b) L. Guo, J.
Sun, X. Ji, J. Wei, Z. Wen, R. Yao, H. Xu, Q. Ge, Commun. Chem.
Ni/C, Fe/C, and bimetallic NiFe/C catalysts with different Ni/Fe
ratios (3:1, 2:1, 1:1, 1:2 and 1:3) were synthesized via incipient
wetness impregnation method according to the previous study.[9]
2
018, 1 (1), 11.; c) C. M. Killian, L. K. Johnson, M. Brookhart,
Briefly, calculated amounts of Ni(NO
3
)
2
·6H
2
O
and/or
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Entry for the Table of Contents
Biomass Conversion
Zihao Zhang, Wenwen Lin, Yafei Li,
Francis Okejiri, Yubing Lu, Jixing
Liu, Hao Chen, Xiuyang Lu, Jie
Fu*__Page – Page
Heterogeneous Non-noble Catalyst
for Highly Selective Production of
Linear α-Olefins from Fatty Acids: A
Discovery of NiFe/C
Herein we report NiFe/C bimetallic catalyst, composed of NiFe alloy in the material bulk
and a surface mixture of NiFe alloy and oxidized NiFe species, exhibiting a
δ+
heptadecene yield of 70.1% with selectivity to 1-heptadecene as high as 92.8% at just
1
90 °C.
7
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